Having very similar issue with my LX9 flight from KORD to LSZH. Used the fuel planner just like u got similar number added another 4 tons on top and still -0.6 EFOB. I am about 1890 nmi away and 16000 kg FOB with 542 kts GS and 2700 kg/h burn rate. Im not gonna make it. I decided to slew thru some waypoints since i cant refuel in the air.